Operation
An operation is defined as follows in the UML 2.0 specification:
An operation is a behavioral feature of a classifier that specifies the name, type, parameters, and constraints for invoking an associated behavior.
The MDSD meta model defines operations as follows:
An operation represents a service delivered by a system.
Actor
An actor is anything that interacts with the system. Examples of actors include
users, other systems, and the environment, including time and weather. There is often confusion between users and workers. In systems engineering, users are
external to the system, and thus are actors. The specification of workers in a system is captured in the worker
Locality
Finally, we explain a concept introduced by Cantor to facilitate reasoning about the distribution of functionality across physical resources, localities.
A locality is defined as a member of a system partition representing a generalized or abstract view of the distribution of functionality. Localities can perform operations and have attributes appropriate for capturing
Localities can be represented either as stereotyped SysML blocks or as stereotyped UML classes.
Associated with localities are connections. Figure
3This document discusses the difference between actors and workers, but does not deal in detail with the worker viewpoint.
4Original discussion of localities occurs in M. Cantor, RUP SE: The Rational Unified Process for Systems Engineering, The Rational Edge, November 2001, http://www.ibm.com/developerworks/rational/library/content/RationalEdge/archives/nov01. html
20Model Driven Systems Development with Rational Products
